The second Triumvirate was formed by Octavian, Caesar's successor and grandnephew; Marc Antony, Caesar's friend and assistant; and Lepidus, who had been leader of Caesar's military. The government of the three men resulted in Octavian becoming absolute ruler of the Roman empire.
<u>Publius, on the other hand, was a Roman noble who commanded the abolition of the Roman monarchy.</u>
The error presented in this sentence is that the antecedent of the pronoun “it” is not clear stated. To my mind, the pronoun "it" can refer to “spare time" or “reading”.